1. Field of the Invention
This invention generally relates to semiconductor device fabrication and more particularly to systems for processing a semiconductor wafer.
2. Description of the Related Art
Specialized wafer processing systems are used to process semiconductor wafers into electronic devices. In most wafer processing systems, a carrier containing wafers is loaded into a loading station and transferred to a loadlock. Subsequently, a robot picks up a wafer from the carrier and moves the wafer into a reactor. The wafer is processed in the reactor according to a recipe. Once the wafer has been processed, the robot picks up and transfers the wafer back to the carrier in the loadlock. The carrier is then moved out of the loadlock and back into the loading station.
Gate valves are routinely employed in a variety of circumstances where wafers are moved from an area at a first pressure to an area at a different, second pressure. In general, the gate valve is a device which is used to isolate operational areas in a wafer processing environment, such that the internal pressures within the operational areas can be varied. The gate valve also reduces particulate contamination between operational areas, which may otherwise be problematic to certain wafer processes.
Unfortunately, the use of gate valves in the processing system also has drawbacks. For example, gate valves generally include large numbers of exposed joints, bearings, hinges, and the like, which generate particulates whenever the gate valve is actuated. These particulates can deposit on the wafers and interfere with the processing operation. Moreover, such joints are difficult to lubricate in a low pressure environment, where the lubrication fluid quickly vaporizes. In addition, location of the gate valve within the processing system usually increases the size of the system. Typically, the increased size of the system, increases the time and power required to draw a vacuum, as well as increasing the capital costs associated with manufacturing the system.
For these reasons, it would be desirable to provide a wafer processing system which does not require vacuum isolation between operational areas of the processing system.
The present invention provides a wafer processing system which requires no isolation between the operational areas within the processing system. The system of the present invention includes operational areas, such as a loading area, a transport area, and a reactor or thermal processing area. Advantageously, since there are no isolation devices or gate valves separating the areas, the processing system effectively has each operational area combined into a xe2x80x9csinglexe2x80x9d chamber. Preferably, the single chamber has a single slit valve, hinge door, or other vacuum sealable door disposed proximate to the loading area to allow for the removal/insertion of the wafers into the loading area. Once the door to the loading area has been closed the internal pressure within the chamber can be kept uniform throughout each operational area.
In one aspect of the invention, a wafer processing apparatus is provided which includes a chamber. Within the chamber are a loading area, a thermal processing area; and a transport area. The loading area, the transport area, and the thermal processing area remain in environmental communication during performance of a wafer processing operation in said wafer processing area.
In another aspect of the invention, a system is provided for processing a semiconductor wafer. The system includes a first compartment configured for receiving wafers to be processed. The system also includes a second compartment disposed adjacent to the first compartment, which includes a transport mechanism operable for transporting the wafers. A third compartment is disposed adjacent to the second compartment, which is used for thermally processing the wafers. The first compartment, the second compartment, and the third compartment are in environmental communication while the wafer is being thermally processed in the third compartment.
A processing system which includes the operational areas combined together in effectively a single chamber removes the possibility of pressure fluctuations from occurring during processing. Because the operational areas in the chamber are under one pressure, the wafer throughput can be increased. Further, since there is one chamber volume there is no need for multiple pumps in the system. The present invention is particularly useful in thermal processes, such as annealing and some chemical vapor deposition processes.
Other uses, advantages, and variations of the present invention will be apparent to one of ordinary skill in the art upon reading this disclosure and accompanying drawings.